Previous work on this project has established the feasibility of monitoring small changes in lung water content by noninvasive microwave transmission phase measurements in isolated dog lungs and in anesthetized dogs. The objectives of the present work are to adapt the techniques to clinical use. Extensive use of a previously developed computer program will further quantify the amount of microwave phase change produced by a change in lung water content. Microwave measurements will be made on renal failure patients and physically normal, schizophrenic patients during dialysis and hemofiltration. This procedure will provide an excellent human model of pulmonary edema, since the impact of removal and addition of varying amounts of fluid under closely controlled, clinically supervised conditions can be evaluated.